Polysilicon gate depletion effect on deep-submicron circuit performance

By integrating the efforts in process, device and circuit simulations, this paper investigates the polysilicon-gate depletion effect (PDE) on performance of circuits composed of deep-submicron transistors. The DC and AC components of PDE on circuit performance are separated for the first time. The study delineates quantitatively the competing effect between the DC and AC PDE. Results of this study suggest the following: (i) PDE degrades circuit speed through dominance of the DC component in the competing effect. Reduction of gate oxide thickness lessens this DC PDE dominance behavior. (ii) Circuit speed degradation due to PDE becomes more significant during low-power operation. (iii) The above phenomenon in (ii) can be substantially improved by thinning the gate oxide thickness